GIFSQ Tools · Module 10 — Packaging & Shelf-Life · Tool 193 of 500
Plan a shelf-life study: how many sampling points, how many samples and how many weeks it runs, from the target shelf life, the sampling interval and the replicates per point.
Try sample values — fills the form with the worked example below.
–
Sampling points
–
Total samples
–
Study length (weeks)
Equation: Sampling points = floor(target ÷ interval) + 1 (day 0 plus each interval to the target). Total samples = points × replicates. Study length (weeks) = target (days) ÷ 7.
Method: Shelf-life study planning: sample at day 0 and at regular intervals through the target life, with replicates at each point so the trend can be judged, per the usual accelerated and real-time study practice.
Assumptions: the target and interval are in the same time unit after conversion; a month is taken as 30 days.
Limitations: the plan covers the sampling schedule only — it does not set the quality limits, the storage conditions or the pass criteria; those come from the study protocol.
Rounding: points and samples are whole numbers; weeks to 2 decimal places; intermediates unrounded.
This is a calculation aid, not a laboratory report — confirm against your accredited method before citing a value.
Method: Shelf-life study planning: sample at day 0 and at regular intervals through the target life, with replicates at each point so the trend can be judged, per the usual accelerated and real-time study practice.
Assumptions: the target and interval are in the same time unit after conversion; a month is taken as 30 days.
Limitations: the plan covers the sampling schedule only — it does not set the quality limits, the storage conditions or the pass criteria; those come from the study protocol.
Rounding: points and samples are whole numbers; weeks to 2 decimal places; intermediates unrounded.
This is a calculation aid, not a laboratory report — confirm against your accredited method before citing a value.
Worked example: A 180-day target sampled every 30 days with 3 replicates: points = 180 ÷ 30 + 1 = 7; total samples = 7 × 3 = 21; study length = 180 ÷ 7 = 25.71 weeks.
Enter values above to see results.
Always include day 0 and a point at or beyond the target life; add a safety margin of one extra interval where the protocol allows. Tool 193 of 500 — GIFSQ
